POP

POP

一 What is POP packaging?

     PoP (Packaging on Packaging), also known as stacked packaging, is one of the very popular three-dimensional overlay technologies developed for IC packaging of mobile devices and can be used for system integration.

    PoP is composed of an upper and lower package stacked together. The interconnection between the bottom package and the upper package and between the bottom package and the motherboard is achieved through a solder ball array. Typically, companies purchase the bottom package components and the upper package components separately and solder them together during the system board assembly process. The bottom package of the stacked package is generally a baseband component, or an application processor, etc., while the upper package can be a memory, etc. 

二 Where is PoP packaging generally used?

     In the field of logic circuit and memory integration, package-on-package (PoP) has become the industry's first choice, mainly used to manufacture high-end portable devices and advanced mobile communication platforms used in smartphones.

     Because this technology can stack high-density logic cells. The PoP product has two packages, one package on top of the other BGA package, and the two packages are combined with solder balls. This kind of packaging integrates logic and memory components into different packages. Logic + storage is usually 2 to 4 layers, and storage PoP can reach 8 layers. Generally, mobile phones use PoP packaging to integrate the application processor and memory.

三What are the advantages of PoP packaging?

1. It provides OEMs and EMS with an effective logic and memory 3-D integration platform

2. Simplified business logistics for stacking

3. Allows integrated control at the system level, thus facilitating the optimization of stack combinations

4. Eliminate margin stacking and expand technology reuse

5. It helps mitigate the impact of the high costs typically associated with multimedia processing

6. Make large-scale customization of the system possible to meet various usage needs

四Limitations of PoP encapsulation

1. The appearance of PoP is relatively high;

2. PoP requires certain stacking technology (technical points);

3. Due to the multi-layer structure, it becomes more difficult to use X-ray to detect the solder joints of each layer.

五Conventional welding process for PoP packaging

     PoP process flow There are currently two ways to assemble PoP. One is the prefabricated PoP process, that is, the multi-layer packages of the PoP are stacked together, welded into a component, then mounted on the PCB, and finally reflowed. One is to package the bottom BGA and top BGA on the PCB in sequence during the board PoP process, and then reflow them once.